A. Field of the Invention
The geared wheelchair ramp is a system that allows a wheelchair 4 and its occupant to ascend and descend horizontal level changes either assisted or unassisted. The invention consists of simple modifications to the wheelchair 4 along with floor or wall mounted guide tracks 2,3 to support and direct the wheelchair 4. The wheelchair 4 is powered by the use of mechanical advantage gained by the use of small drive gears 5 mounted on the wheelchair drive wheels 7. The system is a direct replacement for conventional ramps 1 that requires only a fraction of the space while requiring the same amount of effort to make the level change. There are no motors or electric controls required, and when mounted in a stairway the system does not prevent the use of the stairway.
B. Description of Prior Art
The most common ways for a wheelchair occupant to transit between different horizontal levels are ramps, elevators, and mechanical lifts. Elevators and mechanical lifts use motors and guided cars or platforms to lift the wheelchair between floors. They rely upon an outside power source and are generally custom fabricated for each installation. Problems associated with both elevators and mechanical lifts include expense and lead-time requirements inherent in custom-made apparatus, and complexity of maintenance. The number of moving parts in such systems increases the likelihood of component failure and consequent downtime.
Ramps are simple inclined floor planes with handrails of prescribed height and configuration. The Federal Americans with Disabilities Act regulates the design of such ramps and sets maximum slope at twelve units of run for each unit of rise. The result is that very long ramps are required for only moderate level changes. The costs and space requirements involved are often prohibitive. Therefore, what is needed is a wheelchair lift system that functions like a ramp of accepted proportions, but that requires less space and is less expensive to install. Such a system should allow the wheelchair occupant to transit the level change using no more effort than what is required to use a conventional ramp, either with or without assistance. It must also not block the use of stairs and must be made of simple components which are easy to install in the field and have a minimum of moving parts. The result would be a system with the simplicity of a conventional ramp but that fits into the space of a mechanical lift or elevator.